Not so long ago, George Bush avoided any parallels between Iraq and Vietnam like the plague, but yesterday there was no holding him back. Mr Bush went through the "lessons" not just of Vietnam, but of Japan and Korea, throwing in Graham Greene's Quiet American for good measure.

But before we get to issues of interpretation, it is worth remembering that Mr Bush was addressing army veterans in Kansas City. As Paul Rieckhoff points out at the Huffington Post, the Bush administration can hardly boast of its good treatment of war veterans. The Washington Post highlighted that neglect in its series on the Walter Reed hospital scandal.

As Rieckhoff writes: "If we're going to talk about the legacy of Vietnam, we need to remember what happens when a nation fails to take care of its veterans. We cannot abandon another generation of combat vets to untreated mental health problems, substance abuse, unemployment, homelessness, and suicide."

On the Vietnam analogy itself, few would quarrel with the assertion that the US defeat was followed by years of upheaval. But it does not follow that the US should necessarily stay in Iraq for years to come. That is the argument made by seven infantrymen and non-commissioned officers who have just finished their tours in Iraq.

Although written before Mr Bush made his speech, their remarkable opinion piece in the New York Times provides a powerful antidote to Mr Bush's denial of reality dressed up as a bogus history lesson. For starters, the US did not suddenly pull out of Vietnam but took four years to bring back its troops.

"In the end, we need to recognise that our presence may have released Iraqis from the grip of a tyrant, but that it has also robbed them of their self-respect. They will soon realise that the best way to regain dignity is to call us what we are - an army of occupation - and force our withdrawal," they write.

Back in 2006, when Mr Bush first started drawing comparisons between Iraq and Vietnam, the MSNBC anchor, Keith Olbermann, mounted what still remains one of the most effective demolitions of the president's "lessons from Vietnam".

Mr Olbermann drew five lessons from the US defeat, one of which was: "If you don't have a stable local government to work with, you can keep sending in Americans until hell freezes over and it will not matter."

But his primary lesson was: "... If you try to pursue a war for which the nation has lost its stomach, you and it are finished. Ask Lyndon Johnson."